British police are reportedly preparing the ground to make their first arrests in the hunt for Madeleine McCann. Scotland Yard detectives flew out to Portugal on Sunday night to interview three burglars who were in the area when the 3-year-old went missing, the Daily Mirror said.

Mobile phone records show the men made numerous calls to each other in the hours after she disappeared while on a family holiday in Praia da Luz in May 2007, it is claimed.

A spokeswoman for the Met Police confirmed the Crown Prosecution Service has sent an International Letter of Request to Portuguese authorities on behalf of the Metropolitan Police.

She declined to give details or discuss what the letter contained.

A spokesman for Madeleine's parents, Kate and Gerry McCann, told the Mirror he believed it was likely the burglars were the targets.

"The letter is a significant development. It is necessary for British police to request the ­Portuguese authorities allow them to operate on their turf" he said.

"It means they have the intention of arresting and interviewing X, Y or Z. We don't know who they have their sights on but it's likely it is the burglars. Whether the Portuguese will co-operate remains to be seen. It is a very sensitive issue with differences they have had".

This age-progressed photo of Madeleine was also circulted last year

"Police want to be given a chance to arrest key suspects. It doesn't prove they have Madeleine but it will rule them in or out of the investigation and that is important Kate and Gerry don’t want to build up their hopes too high but they realise it could be a significant new lead" he added.

It would be Scotland Yard's first arrests since it set up Operation Grange in 2011 to review Madeleine's disappearance.

It is claimed that days before the little girl vanished, the gang raided another holiday flat in the Algarve resort, disturbing a child. The youngster's parents reportedly interrupted the burglars who fled.

Madeleine vanished from her holiday apartment while her parents were dining in a tapas bar 90 yards away.

Portuguese police reopened their investigation last year, more than three years after it was shelved.

It is running in parallel with the Scotland Yard inquiry but the Met Police commissioner has called for the two forces to work together as one team.